This specification relates to search engines.
A search engine may generally be described as any program that executes a search and retrieves stored data. However, based on the task at hand, a search engine can be configured in a variety of different ways. For example, some search engines may be configured to perform keyword-based search and retrieval. Such search engines may identify relevant search results based, at least in part, on the number of times a search term appears in a particular resource, or the particular resource's metadata. Alternatively, or in addition, some search engines may identify search results as being responsive to a query because a resource provider paid the search engine provider a sum of money to return the provider's resource(s) in response to search queries that include a particular search term. However, the aforementioned ways that a search engine can identify search results responsive to a query are merely exemplary.
A search engine can also be configured to identify search results responsive to a query in a variety of other ways. A custom configuration of a search engine can be employed, as necessary, to solve particular problems related to search and retrieval. Customizing a search engine can include altering the way a search engine executes a search, identifies relevant search results, ranks identified search results, or the like.